.. _sgp40_sht4x: SGP40 and SHT4X: High accuracy digital I2C humidity sensor and multipixel gas sensor #################################################################################### Description *********** This sample application periodically measures the ambient temperature, humidity and a raw gas sensor value from an SGP40 and SHT4X device. The result is written to the console. You can choose to use the on-chip T/RH compensation of the SGP40 by feeding the values measured by the SHT4X into it. This is enabled in the Application by default, you can turn it off by setting ``APP_USE_COMPENSATION=n``. The SHT4X has the option to use a heater which makes sense for specific environments/applications (refer to the datasheet for more information). To make use of the heater have a look at the Kconfig options for this application. References ********** - `SHT4X sensor `_ - `SGP40 sensor `_ Wiring ****** This sample uses the SHT4X and SGP40 sensor controlled using the I2C interface. Connect Supply: **VDD**, **GND** and Interface: **SDA**, **SCL**. The supply voltage can be in the 1.7V to 3.6V range. Depending on the baseboard used, the **SDA** and **SCL** lines require Pull-Up resistors. Building and Running ******************** This project outputs sensor data to the console. It requires a SHT4X and a SGP40 sensor. It should work with any platform featuring a I2C peripheral interface. This example has an example device tree overlay for the :ref:`blackpill_f411ce` board. .. zephyr-app-commands:: :zephyr-app: samples/sensor/sgp40_sht4x :board: blackpill_f411ce :goals: build flash Sample Output ============= .. code-block:: console *** Booting Zephyr OS build v2.6.0-rc1-315-g50d8d1187138 *** SHT4X: 23.64 Temp. [C] ; 30.74 RH [%] -- SGP40: 30531 Gas [a.u.] [00:00:00.250,000] SGP40.sgp40_init: SGP40: Selftest succeeded! SHT4X: 23.66 Temp. [C] ; 32.16 RH [%] -- SGP40: 30541 Gas [a.u.] SHT4X: 23.63 Temp. [C] ; 30.83 RH [%] -- SGP40: 30522 Gas [a.u.] The datasheet states that the raw sensor signal for the SGP40 ist proportional to the logarithm of the sensors resistance, hence it is labeled as [a.u.] (arbitrary units) in the example.